1. FIELD OF THE INVENTION
The present invention relates to an improvement of a remote controlled relay.
2. DESCRIPTION OF THE RELATED ART
The same inventors have proposed a remote controlled relay shown in FIGS. 3 to 9 in a prior application, filed on Nov. 27, 1991 in the U.S. (application Ser. No. 07/799,124). FIG. 3 is a cross-sectional side view showing the related remote controlled relay when the relay is switched off (hereinafter abbreviated as OFF). FIG. 4 is a plan view of the related remote controlled relay shown in FIG. 3. FIG. 5 is a cross-sectional side view of the related remote controlled relay when the relay is switched on (hereinafter abbreviated as ON). FIG. 6 is a plan view of the related remote controlled relay shown in FIG. 5. FIG. 7 is a cross-sectional side view showing main parts of the related remote controlled relay in a condition shown in FIG. 3. FIG. 8 is a cross-sectional side view showing the main parts of the related remote controlled relay in the condition shown in FIG. 5. FIG. 9 is a circuit diagram showing a circuit of the typical remote controlled relay.
In the figures, a housing 1 consists of a base member 1A and a cover member 1B. The housing 1 has: a pair of grooves 1a formed on side walls 1e and 1f in the vicinity of a bottom face 1g, whereto fixing bands (not shown in the figure) are to be coupled; a pair of protrusions 1b in the vicinity of the center part of the bottom face 1g, whereby the housing 1 is to be fixed on a DIN standard rails (not shown in the figure); and an opening 1c on its top face 1h. The base member 1A and the cover member 1B respectively have four coupling holes 1d and four protrusions (not shown in the figure). Each hole 1d on the base member 1A are provided to face and to couple each hole formed on the protrusion of the cover member 1B. The base member 1A and the cover member 1B are connected and fixed by rivets 2 which are fit in the holes 1d.
As shown in FIG. 3 or 5, a driving magnet 3 is positioned substantially in the center of the housing 1, wherein the driving magnet 3 is provided in a manner that the moving direction of the plunger 4 is perpendicular to the bottom face 1g of the housing 1. The driving magnet 3 is a polarized-type, and the plunger 4 is slidably provided on a center hole of a bobbin 6 as shown in FIGS. 7 and 8, whereon an electromagnetic coil 5 is wound. The plunger 4 has upper and lower armatures 4a, 4b on both ends. A first yoke 7 encloses the bobbin 6 and has an opening 7a from which a rod part 4c of the plunger 4 projects upwards.
Permanent magnets 8 are provided on inner walls of the first yoke 7, for example, at right and left hands in the figures, and both permanent magnets 8 are fixed on the first yoke 7 in a manner that one face of the poles of the magnets 8 contact to the inner face of the first yoke 7. The other faces of the magnets 8 having the other polarity are fixed to second yokes 9 which have a channel-section. The second yokes 9 are provided in a manner that brim parts the bobbin 6 of the coil 5 are fit in the channel-section parts of the second yokes 9.
A link 11 for transmitting the movement of the plunger 4 to a moving contact 10 is provided above the driving magnet 3. The link 11 is rotatably pivoted on the housing 1 by a pin 12. An end 11a of the link 11 is pin-joined to an end of the rod part 4c of the plunger 4 by a connecting pin 13.
A moving unit 14 comprises: an insulating member 16 which is pin-jointed to an end thereof to the other end 11b of the link 11 by a pin 15; a moving base member 17 which is slidably fit in a guide groove 16a formed on the other end of the insulating member 16 and whereto the moving contact 10 is fixed; and a compression spring 18 for supplying a pressure to the moving contact 10. The moving contact 10 faces a fixed contact 20 which is fixed on a main terminal 19 whereto a main circuit is connected in a manner that the moving contact 10 is driven toward and away from the fixed contact 20 by movement of the moving unit 14.
Rod-shaped protrusions 16b formed on both sides (forward and backward of FIG. 5) of the insulating member 16 are slidably engaged in grooves (not shown) of the base member 1A and the cover member 1B. Thereby, the moving unit 14 is driven by the movement of the plunger 4 in a manner that the moving contact 10 moves toward and away from the fixed contact 20. The moving base member 17 is electrically connected to another main terminal 22, whereto the main circuit is connected, by the shunt 21.
A pair of remote control terminals 23 are provided on an upper part of the side 1e of the housing 1 whereto wires of a remote controller are connected. One of the remote control terminals 23 is connected to a lead wire 5a of the electromagnetic coil 5 and the other remote control terminal 23 is connected to the other lead wire 5b of the coil 5 via diodes 24 and a switch 25 on a printed circuit substrate 26. The circuit diagram of the typical remote controlled relay is shown in FIG. 9.
An operation handle 27 is rotatably pivoted on the housing 1 by a pin 28 on a point opposite to the link 11 against the plunger 4. The operation handle 27 is coupled to the rod part 4c of the plunger 4 by a coupling pin 13, wherein an end of the coupling pin 13 is press-fit in a coupling hole 29. Thereby, the operation handle 27 is rotated by reciprocating movement of the plunger 4 in directions opposite to the rotation directions of the link 11. The operation handle 27 has a knob 27a which is manually operated from the outside of the housing 1. The knob 27a is positioned in the opening 1c of the housing 1 (consisting of the base member 1A and the cover member 1B). On parts of the surface of the operation handle 27 which are positioned symmetrical to the knob 27a, indications 27b (shown in FIGS. 4 and 6) for indicating the ON state and OFF state of the relay are provided. The indications 27b are observed through the opening 1c. Furthermore, the operation handle 27 has an operation part 27c which contacts an actuator 25a of the switch 25 for switching the switch 25.
Next, operation of the above-mentioned related remote controlled relay is described.
FIG. 3 shows the OFF state when the remote controlled relay is switched off. At this time, the plunger 4 is held in a manner that the armature 4a is attracted to the bottom face of the first yoke 7 by the magnetic flux of the permanent magnet 8, and the moving contact 10 and the fixed contact 20 are respectively at stable positions wherein the contacts 10 and 20 are apart from each other.
In such a state when the main circuit is opened, the electromagnetic coil 5 is excited by switching on a remote control switch 30 (shown in FIG. 9) which is connected to the remote control terminals 23, the magnetic flux produced reduces the magnetic attraction force of the permanent magnets 8 on the armature 4a of the plunger 4 and increases the magnetic attraction force of the coil 5 on the other armature 4b of the plunger 4. Thereby, the plunger 4 is driven in a direction shown the arrow in FIG. 7, the link 11 is rotated a counterclockwise direction, the moving contact 10 is moved to the fixed contact 20 and finally the main circuit is closed by the contacting of the moving contact 10 and the fixed contact 20. In this state, the armature 4b of the plunger 4 is attracted and held on an upper inner face of the first yoke 7. At this time, the operation handle 27 is rotated in a clockwise direction by the movement of the plunger 4 and the indication is changed from OFF to ON. In such a sequence of operations, the operation handle 27 drives the actuator 25a of the switch 25 and thereby the switch 25 is turned on or off.
When the main circuit is turned on, the remote control switch 30 shown in FIG. 9 is switched on, the electromagnetic coil 5 is excited to produce magnetic flux for reducing the magnetic attraction force of the permanent magnets 8 on the armature 4b of the plunger 4 and for increasing the magnetic attraction force of the coil 5 on the other armature 4a of the plunger 4. Thereby, the plunger 4 is driven in a direction shown by the arrow in a FIG. 8, the link 11 is rotated in clockwise direction, the moving contact 10 is moved away from the fixed contact 20, and finally the main circuit is opened by moving the moving contact 10 from the fixed contact 20. In this state, the armature 4a of the plunger 4 is attracted to the bottom face of the first yoke 7, that is the initial stable state. At this time, the operation handle 27 is rotated in a counterclockwise direction by the movement of the plunger 4 and the indication is changed from ON to OFF. In such a series of the operation, the operation handle 27 drives the actuator 25a of the switch 25, and thereby the switch 25 is turned off.
For manually switching on and off the main contacts from outside of the housing 1, the knob 27a of the operation handle 27 is driven by hand, and the plunger 4 is directly driven, thereby switching the contacts on and off. In manual operation, a removing force, larger than the attraction force of the permanent magnet for attracting the plunger 4 on the first yoke 7, is directly applied on the plunger 4 by hand, and thereby the plunger 4 is forcibly moved and shifted to the other stable state. During manual operation, the movement of the moving unit 14 and the switching operation of the switch 25 are the same as the aforementioned remote control.
In the above-mentioned related remote controlled relay, the coupling pin 13 is tightly fit in the coupling hole 29 of the operation handle 27, and hence the operation handle 27 and the plunger 4 are uncooperatively pin-jointed by the coupling pin 13. When the operation handle 27 is erroneously stopped at a neutral position (an intermediate position between the OFF position shown in FIG. 7 and the ON position shown in FIG. 8), both of the armatures 4a and 4b of the plunger 4 are not attracted to the first yoke 7. Namely, the plunger 4 is deadlocked at a neutral position of the driving magnet 3.